5.11 Tactical started in Modesto, California as a clothing line created by mountain climber Royal Robbins. Upon reaching the top of a climb in Yosemite California, he noticed that the trousers that he was wearing were not suited to climbing. Robbins decided that he needed to design something more durable and with better functionality. He owned a boot and clothing company and began manufacturing pants by the name of "5.11" that had a trademarked tactical strap and slash pocket design in 1968.
The name “5.11” comes from the highest rock climbing difficulty level that was listed in the Yosemite Decimal System at Yosemite National Park, which was developed by Robbins in the 1950s. The difficulty level is somewhat jokingly defined as, “After thorough inspection, you conclude this move is obviously impossible; however, occasionally someone actually accomplishes it".
Robbins sold a 51% stake in his company to Dan Costa in 1999, who, after a lot of streamlining, noticed that the 5.11 Tactical pants were becoming popular at the FBI Academy in Quantico, Virginia.
Costa bought the entire company in 2002 and ended up selling Royal Robbins Clothing back to Robbins in 2003, but kept the 5.11 Tactical brand and spun off a whole new company called 511 Inc or 5.11 Tactical. Partnering with the FBI, Dan Costa and his co-partner and creative genius Francisco Morales began creating additional tactical apparel and improving on the existing line. In 2006 5.11 Tactical was ranked No. 211 on Inc. magazine's list of the 500 fastest- growing companies in the nation.